- autogyroAn aircraft in which lift is provided by unpowered rotating wings and thrust is provided by a conventional propeller.
- auto-Reflexive, regarding or to oneself.
- autotrophAny organism that can synthesize its food from inorganic substances, using heat or light as a source of energy.
- chemoautotropha simple microorganism, such as a prokaryote (bacteria and Archaea), that derives its energy from chemical processes rather than photosynthesis
- photoautotrophan organism, such as all green plants, that can synthesize its own food from inorganic material using light as a source of energy
- selfnameA proper name; a name for one's own self, as opposed to one's family; one's real name.